Malcolm Scott, formerly of Cardinal Wiseman school, Middlesex, visited the pornographic websites before and during school hours, the General Teaching Council of England heard.

Mr Scott, who was not present or represented at the hearing, admitted misconduct.

The hearing was told that on June 30, 2003, Adrian Krezeptowski, the school’s data communications manager, and a sixth-former on work experience, discovered during routine work on Mr Scott’s computer that pornographic sites had been visited.

Mr Krezeptowski alerted Paul Patrick, the headteacher, and the police were called.

The computer was monitored over the next few days and it was found that visits were made to sites between 6.42am and 8.09am on July 2, and between 6.42am and 8.29am and 9.49am and 10.28am the following day. A credit-card site called “Only Tens” had been accessed and the computer’s memory erased.

Bradley Albuery, presenting officer, said Mr Scott had said in an email to him that Only Tens was not about underage girls, but where women were rated from one to 10. He also said that his computer had received unwanted pop-ups to pornographic sites.

Mr Scott became a technology teacher at Cardinal Wiseman in 1997, before leaving to become head of department at an Essex school, in 1999. He returned in January 2000.

Mr Patrick said: “He was a good teacher and when he left we gave him a good reference. He found it very challenging and wished to return. I was very happy to have him back. I felt him to be a very competent teacher.” Mr Patrick said that he was aware when he re-hired Mr Scott that he suffered from depression.

Robert Millea, GTC chair, said: “We cannot overlook the fact that that Mr Scott viewed pornography and there was a good chance pupils could have viewed the material,” he said.

Mr Scott can reapply to be put on the teaching register in two years’ time.

A police investigation into Mr Scott’s use of pornographic sites was dropped.